Fabrication of nanoparticle and protein nanostructures using nanoimprint lithography

Nanoimprint lithography (NIL) was used as a tool to pattern self-assembled monolayers (SAMs) on silicon substrates because of its ability to pattern in the micrometer and nanometer ranges. The resulting polymer template behaved as a physical barrier preventing the formation of a SAM in the covered areas of the substrate. After polymer removal, patterned SAM were obtained. The versatility of the method was shown in various nanofabrication schemes. Substrates were functionalized with a second type of silane adsorbate. Two types of substrates were thus made (i) topographical templates with a chemical functionalization and (ii) chemically patterned, topographically flat, substrates. Nano-objects such as molecules, nanoparticles and proteins were directed onto these two types of substrates. Two types of interactions were used to direct the assembly of these nanoobjects namely electrostatic and supramolecular interactions. The advantage of supramolecular interactions is that the binding strength between the host and guest is known, the interaction is reversible and the attachment of the nano-object is made through a specific site, allowing control over the position of the nano-objects.